Phalanger - The PHP language compiler for .NET Framework. DataDesigner - Standards based .Net document server. With peer-to-peer content exchange abilities. [Public Domain] VNC-Client for .NET - A VNC-Client written in C# using the .NET Framework. VNC is a remote display system, which allows the user to access the desktop of a remote machine. [Open source, GPL] Skelta - Workflow - A embeddable .NET based workflow framework Spring.NET - An application framework that provides capabilities like dependency injection and Aspect Oriented Programming (AOP) for building enterprise .NET applications. mojoPotal - mojoPortal is an open source content management system and web site framework portal for .NET. SharpDevelop - An open source integrated development environment written in C#. Passage .Net - Open Source .NET Portal Software - An open source enterprise portal and content management system written in C# and has a BSD license. Paint.NET - A freeware photo editor that teaches many aspects of Windows forms development. Written entirely in C#. OpenXML Writer - OpenXML Writer is an opensource text editor for creating WordprocessingML files (.docx) that is created with the .Net Framework. NUnit - An unit testing framework that is open source written in C#.